1. Field of the Invention
The present invention relates to a color chart processing apparatus, a color chart processing method, and a color chart processing program for acquiring spectral image information of a subject, and determining correspondence between a color of the acquired image and a predetermined color chart.
2. Description of the Related Art
Color management has been conventionally performed in numerous fields. Colors of objects are typically determined based on sensory evaluation using a color chart. For example, in the dentistry field, a color chart called a shade guide is used to determine which grade an artificial denture is classified to when the artificial denture is produced. For example, a leaf color chart is used to determine an agricultural crop such as rice plant. By checking a crop against the leaf color chart, a current growing condition is known. Growth and development management is thus performed to adjust the amount of fertilizer. The application of color charts is not limited to the dentistry and agricultural fields. The color charts are used for diagnosis and examination in a variety of other fields, such as coating painting of cars, painting of buildings, foods, and clothes.
Each color is identified using a number in the color chart (color chart number). Experienced users and specialists visibly check an object to be examined against a color chart, thereby determining the color chart number. There occur variations inherent to a user himself, variations from user to user, and variations in illumination conditions under which a subject is placed. It is thus difficult to accurately identify the color chart number.
Japanese Unexamined Patent Application Publication No. 7-120324 (hereinafter referred to Document 1) discloses a technique of color classification using a camera system. In the disclosed technique, a multi-spectral camera is used to classify grade using a multi-spectral image captured by the camera. In comparison with an ordinary RGB camera, the multi-spectral camera substantially increases a color chart determination accuracy level.